package com.atcjx.MyUtils.File;

import javax.imageio.ImageIO;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;

/**
 * 图片压缩Utils
 *
 * @author worstEzreal
 * @version V1.1.0
 * @date 2018/3/12
 */
public class PicUtils {
    /**
         * 将图片压缩到指定大小以内
         *
         * @param srcImgData 源图片数据
         * @param maxSize 目的图片大小
         * @return 压缩后的图片数据
         */
        public static byte[] compressUnderSize(byte[] srcImgData, long maxSize) {
            // 每次压缩的比例
            double scale = 1.4;
            byte[] imgData = Arrays.copyOf(srcImgData, srcImgData.length);

            if (imgData.length > maxSize) {
                do {
                    try {
                        imgData = compress(imgData, scale);
                        System.out.println(imgData.length);
                    } catch (IOException e) {
                        throw new IllegalStateException("压缩图片过程中出错，请及时联系管理员！", e);
                    }

                } while (imgData.length > maxSize);
            }

            return imgData;
        }

        /**
         * 按照 宽高 比例压缩
         *
         * @param srcImgData 待压缩图片输入流
         * @param scale 压缩刻度
         * @param byte 输出
         * @return 压缩后图片数据
         * @throws IOException 压缩图片过程中出错
         */
        public static byte[] compress(byte[] srcImgData, double scale) throws IOException {
            BufferedImage bi = ImageIO.read(new ByteArrayInputStream(srcImgData));
            int width = (int) (bi.getWidth() * scale); // 源图宽度
            int height = (int) (bi.getHeight() * scale); // 源图高度

            Image image = bi.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

            Graphics g = tag.getGraphics();
            g.setColor(Color.RED);
            g.drawImage(image, 0, 0, null); // 绘制处理后的图
            g.dispose();

            ByteArrayOutputStream bOut = new ByteArrayOutputStream();
            ImageIO.write(tag, "JPEG", bOut);

            return bOut.toByteArray();
        }
}
